Capsule for an extraction product, method for the production thereof, and device for brewing coffee

ABSTRACT

A capsule to form a closed interior filled with an extraction product or extract can be perforated in a known manner by perforation elements of an injection device or a discharge device in order to introduce an extraction liquid and to discharge an extraction product produced in the interior of the capsule following an extraction process. The capsule has the shape of a cuboid or a die.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to the preparation of beverages or the like froman extraction material contained in a capsule, for example groundcoffee. It relates in particular to a pierceable capsule as a portionpack and to a method for the production thereof.

2. Description of Related Art

Extraction devices for preparing beverages or the like from anextraction material present in a portion pack are known, for example, ascoffee or espresso machines and continue to enjoy increasing popularity.In many corresponding systems, the portion packs are formed as capsulesin which the extraction material is, for example, closed off in anairtight manner. For the extraction, the capsule is pierced from twoopposite sides. On the first side, extraction liquid—generally hotwater—is introduced. On the second side, the extraction product isdischarged from the capsule. Depending on the beverage to be preparedand the system, a considerable pressure, for example of 5-20 bar, maythereby prevail in the interior of the capsule.

Such capsules must not be confused with—and have to meet entirelydifferent requirements than—portion packs of filter coffee, which areopened by pulling off a foil, removing a cover or the like and are notat any time exposed to an increased pressure. They are equally notcomparable to the outer, aroma-tight packagings of “filter pads”. Inbrewing modules of coffee machines, capsules of the type described hereare often passed through horizontally or vertically by the hot brewingliquid and, as mentioned, are thereby exposed to a considerable pressureinside. This also gives rise to the problem of sealing; after all, thepressurized brewing liquid must not get past the capsule and enter thedischarge device directly.

Aluminum and plastics, for example polypropylene, have become known inparticular as capsule materials. Aluminum capsules keep the extractionmaterial fresh for a long time, but use considerable energy for theirproduction. Polypropylene capsules are advantageous with respect toenergy consumption and disposal, but impose increased requirements onthe piercing mechanism.

Particularly advantageous with respect to material consumption are deepdrawn capsules, which however always have a decidedly conical form.

Available on the market are both, capsules with integrated filteringmeans and capsules that merely comprise a shell around the extractionmaterial, and for which the piercing mechanism therefore has to bedesigned in such a way that extraction material is not undesirablydischarged from the capsule together with the extraction product.

An example of a capsule without integrated filtering means is disclosedfor example in EP 1 886 942.

Available capsules are generally rotationally symmetrical and comprise aperipheral collar, which has a threefold function essential for them towork properly:

-   -   the collar serves for closing the capsule during the filling        operation, in that it comprises an energy director for        ultrasonic welding at a sufficient distance from the interior        space of the capsule or a sufficiently large surface area for        thermal welding;    -   the collar serves for holding the capsule before the brewing        operation;    -   the collar is essential for the sealing during the brewing        operation, as it ensures that no brewing liquid gets past the        capsule and directly enters the discharge device.

In the case of capsules according to the prior art, an additionalsealing function may be assumed by the conical form, which fits veryexactly into a corresponding receptacle of the brewing chamber.

Many of the available capsules are shaped in the form of a cup, i.e.they are rotationally symmetrical about an axis and conical. Often, thecover of the cup-shaped capsule is of a different material compositionthan the actual cup that forms the lateral surface and the bottomsurface. Therein, the injection of the extraction liquid takes placethrough the cover or the bottom surface and the discharge of theextraction product correspondingly takes place through the bottomsurface or the cover respectively. This form of capsule has provensuccessful, both with regard to the mechanical stability and with regardto technical aspects of production.

A particularly problematical issue involves the swirling of theextraction material during the brewing process. During the extractionprocess, liquid flows through the capsule at high speed. If there islimited compaction of the extraction material, it is made to swirlconsiderably during the brewing process. For this reason, it has alreadybeen proposed (EP 1 886 942) that the extraction material is compressedvigorously during the capsule filling process. However, this method israther complex, and the pellet-like consistency of the extractionmaterial achieved by the compression can be lost during thetransportation of the capsule.

A further problematical issue that is often discussed in connection withportion capsules for brewed beverages is the complex packaging, whichadversely affects the energy balance.

BRIEF SUMMARY OF THE INVENTION

It is an object of the invention to provide a capsule for a brewedbeverage or the like that overcomes disadvantages of the prior art andbrings improved solutions in terms of the energy balance andflexibility.

This object is achieved by the invention as it is defined in the patentclaims.

The portion capsule according to the invention is of the type mentionedat the beginning, in which the extraction material is, for example,closed off in an airtight manner and which anticipates obtainingextraction by piercing the capsule on two opposite sides. On the firstside, an extraction liquid—generally hot water—is introduced. On thesecond side, the extraction product is discharged from the capsule.Depending on the beverage to be prepared and the system, the capsulemust thereby withstand a considerable pressure inside it, for example of5-20 bar, in particular, more than 10 bar. However, this does notpreclude the use of the capsule in brewing processes with a lowerpressure, for example of only 1-2 bar—in particular for filter coffee ofthe American style.

The capsule is free from sieving or supporting elements or the likearranged in the interior; it therefore consists, for example, only of acapsule wall of uniform wall thickness, at least on several sides, andthe capsule filling (extraction material).

According to one aspect of the invention, the capsule is in the form ofa cube or cuboid and is free from protruding collars or the like.

In the present case, cuboidal or cube-shaped describes a form that doesnot deviate from the geometrically exact form of a cuboid or cube tosuch an extent that it would be functionally very different; forexample, it includes the form of a truncated pyramid with a rectangularor square base area, wherein the side faces adjoining the base area areinclined with respect to the perpendicular to the base area by only asmall angle of inclination a of, for example, at most 3° or 2°,preferably at most about 1°. As mentioned, the cuboid or cube formexcludes a peripheral collar that protrudes from the capsule body in theplane of an end face and is provided for holding the capsule in guidingslots. The cuboidal or cube-shaped capsule may nevertheless compriseperipheral edges created during production (for example a welding bead),which laterally protrude, for example, by a maximum of 1.5 mm or 1 mm,0.8 mm, 0.6 mm, with particular preference 0.5 mm or less, as a resultof their limited dimensions do not significantly impair the function ofthe cube or cuboidal shape and are also, for example, offset from aplane of an end face.

This form firstly has the great advantage that the extraction materialcan be compressed from various sides, which is not the case with thecup-shaped capsules. In particular, the extraction material can also becompressed when it is already packed in the capsule—by pressing twoopposite side walls toward each other. In the case of cup-shapedcapsules, that is not readily possible in a nondestructive manner. Withpreference, the capsule is formed such that a deformation of twoopposite side walls (or of central points on these side walls) againstan elastic force with a volume-reducing effect is possible. This refersto the state at room temperature and does not preclude a permanentdeformation of a plastic capsule wall in the hot state.

Secondly, there is the advantage of the decidedly improved packability.The filled and sealed capsules can be arranged in series one against theother and stacked one on top of the other in such a way as to obtain astack that is essentially free from intermediate spaces, can also beprovided with a pleasing appearance—for example as a cube—andnevertheless manages with minimal external packaging.

With preference, the capsule can be pierced from every side—that is,every pair of sides lying opposite from each other. This means here notonly that the capsule wall on the side of the cube concerned can beperforated by a corresponding metal tip, but also that the capsulepierced on a pair of opposite sides of the capsule withstands thebrewing pressure when the liquid is introduced and the brewing liquidonly flows away on the extraction side and only at the location of theperforations.

The capsule is closed off in a hermetic and oxygen-tight manner by thewall comprising all sides, edges and corners. Therefore, no separatefoil that entirely or partially covers the capsule and no oxygen-tightbag or the like for the capsule is necessary. In comparison with knownsystems, the amount of waste is much less.

With preference, the capsule consists of essentially the same materialcomposition on all sides. In particular, the capsule may also be ofessentially the same thickness on all sides. In other words, no specialcover foil configured differently than the basic body is necessary.“Essentially the same thickness” may mean, for example, that thethicknesses of the various sides differ by at most 30%.

The cube form is particularly advantageous. In the case of aconfiguration with the same material composition and thickness on allsides, it is immaterial how the cube-shaped capsule is placed into abrewing module of the extraction device (coffee machine or the like).This reduces the risk of incorrect manipulations by the user.

The capsule preferably consists of plastic. An especially preferredmaterial for the capsule is polypropylene (PP). Other materials are alsoconceivable, in particular other plastics that are compatible with food.The wall thickness in the design of a plastic capsule is preferablybetween 0.1 mm and 0.5 mm, for example between 0.2 mm and 0.4 mm, inparticular between 0.25 mm and 0.35 mm.

In designing a plastic capsule, the capsule is preferably produced bydeforming (for example deep drawing) a sheet of plastic. This makes itpossible for a greatly reduced amount of material in comparison withother processes—for example injection molding—to be required. The sheetof plastic may contain an oxygen barrier layer in a way known per se.Previous deep drawn plastic capsules have always been conical, becauseconical forms are in accord with the deep drawing process. In thisrespect, the present invention (or embodiments thereof) takes anentirely new approach, in that a form deviating from the conical ischosen, a form which, as mentioned above, proves to be highlyadvantageous. To this purpose, a deep drawing tool with specialproperties developed specifically for such applications is used.

According to a preferred embodiment of the invention, the capsule isprovided together with a coffee machine or a brewing module of a coffeemachine which comprises the following:

-   -   a first brewing module part, and    -   a second brewing module part, which is movable in relation to        the first part, wherein the first and the second brewing module        part form a discharge device for discharging an extraction        product from the capsule and an injector for introducing an        extraction liquid into the capsule and a brewing chamber formed        to match the shape of the capsule and at least partially        surrounding the capsule during the brewing operation, wherein        the discharge device and the injector each comprise at least one        perforating tip, which perforates the capsule when the brewing        chamber is being closed, wherein    -   the brewing is made to match the afore described shape of the        capsule and acts in a sealing manner in such a way that brewing        liquid introduced into the capsule by the injector can only        reach the side where the discharge device is located by passing        through the capsule.

In other words, this approach abandons a peripheral collar that assumesthe sealing function and instead provides a brewing chamber thatreceives substantially cube-shaped capsules and nevertheless comprisesmeans which bring the brewing liquid under pressure through the capsule.

According to a further preferred embodiment, the brewing module is freefrom holding grooves or the like for holding a collar—not presentaccording to the invention—, but instead the capsule is thrown directlyinto the brewing chamber. This means, for example, that the firstbrewing module part forms a capsule receptacle with a contact surfaceand a lateral guide, the contact surface being positioned in such a waythat the capsule thrown in via the throwing-in position comes to lie onthe contact surface, guided by the lateral guide, that the secondbrewing module part can be moved in relation to the first brewing modulepart for closing the brewing chamber, and that the contact surface andthe lateral guide form part of the wall of the brewing chamber.

Likewise with preference, the brewing module comprises a compressionmeans, by which the capsule is compressed, for example from two lateralsides, which results in improved extraction. The compression means maycomprise, for example, two pins which can be displaced counter to aspring force into the capsule space and are displaced by a guiding camduring the closing of the brewing chamber.

A preferred method for producing the capsule proceeds as follows:firstly, a basic cube body which has five sides and is open on the otherside (or correspondingly other basic polyhedral bodies) is produced froma suitable plastic. This may take place in a packaging productionfactory and by the deep drawing process. Then, the open basic body isfilled with the extraction material in a filling plant. Subsequently,the missing side is fastened to the open basic body as a cover, thecover preferably comprising the same material composition and being ofthe same thickness as the basic body.

According to a first possibility, the fastening is performed along theperipheral edge of the basic body, for example by ultrasonic welding,thermal welding or by adhesive bonding. For this purpose, the basic bodymay initially have a collar which runs around the open side, protrudesinwardly or outwardly and to which the cover is welded or adhesivelybonded. In the case of fastening by means of ultrasonic welding, thecollar may also be provided with an energy director. As a differencefrom known solutions, the energy director may in this case not bearranged as far to the outside as possible but in the vicinity of theinner side. For example, the distance d between the one edge of theenergy director and the plane defined by the inner wall of the capsulemay be no more than 0.7 mm, with preference no more than 0.6 mm, 0.5 mmor 0.4 mm, and, for example, be in the range between 0.2 mm and 0.4 mm.If—as is preferred—the collar protrudes outwardly, the cover may besomewhat larger than the open side of the basic body and, for example,protrudes more or less as far as the outer edge of the collar. After thewelding, the peripheral edge may optionally be at least partiallydetached, for example by punching, in order that at most there are minordeviations from the form of the cube (the corresponding otherpolyhedron).

According to a second possibility, the basic body likewise initially hasa peripheral, outwardly protruding collar. The cover may be flat or—withpreference—outwardly curved. Then, the ultrasonic cut and seal processis used, in which ultrasonic energy is absorbed between a sonotrode anda cutting anvil, with the effect on the one hand of producingcomparatively deep welding, which also has great pressure resistance,and on the other hand of detaching the protruding collar in the weldingoperation itself.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention are described below on the basisof drawings. In the drawings, the same reference signs designate thesame or analogous elements. The drawings are not to scale and to someextent show elements partly corresponding to one another in differentsizes from figure to figure. In the drawings:

FIG. 1 shows a view of a capsule,

FIG. 2 shows a view of a variant of the capsule from FIG. 1,

FIG. 3 shows a view of a further variant of the capsule from FIG. 1,

FIG. 4 schematically shows an approximately cube-shaped, slightlyfrustopyramidal capsule,

FIG. 5 shows piercing via one side of the capsule,

FIG. 6 shows piercing via an edge or corner of the capsule,

FIG. 7 shows a basic body with an auxiliary collar for producing acapsule according to the invention,

FIG. 8 shows a detail of the basic body and of a cover during the methodfor producing the capsule,

FIGS. 9 and 10 show a basic body and a cover for an alternative methodfor producing a capsule according to the invention,

FIG. 11 shows a view of a capsule produced by the method according toFIGS. 9 and 10, and

FIGS. 12 and 13 show representations of a brewing module for operatingtogether with capsules according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

The capsule 1 according to FIG. 1 is cube-shaped and consists ofpolypropylene with a wall thickness of between 0.1 mm and 0.5 mm,preferably between 0.2 mm and 0.4 mm, for example between 0.25 mm and0.35 mm.

For individual portions for coffee to suit continental European drinkingtastes, the outer length of the edges of the cube 1.2 is with preferencebetween 24 and 30 mm, for example between 26 and 27 mm. An outer edgelength of 27.5 mm results in a maximum filling weight of about 8.5 g ofcoffee. However, the capsule size of individual portion capsules mayalso have other dimensions, for example to suit American coffee drinkingtastes. There, the capsules may have an outer edge length of, forexample, up to 34 mm, in particular for example about 32 mm, for afilling amount of about 14-15 g. For such drinking tastes, the pressureof the water introduced may also be correspondingly chosen differently,and for example be only about 1-2 bar instead of the otherwise preferred10-18 bar.

Altogether, a preferred range of the edge lengths is between 24 mm and34 mm.

For introducing the extraction liquid and discharging the extractionproduct, the capsule may be pierced from all six sides 1.1, all twelveedges 1.2 and all eight corners 1.3, the introduction and dischargetaking place with preference on/at sides/edges/corners which areopposite from each other.

In the representation according to FIG. 2 it can be seen that acube-shaped capsule may have edges which are formed as rounded-off edges1.2. Furthermore, there is a collar 1.4, which in FIG. 2 lies on theunderside, runs around the periphery, slightly protrudes laterally andis created during production, which is explained in further detailbelow. As FIG. 3 shows, there may also be a peripheral reinforcement1.6, which is likewise created during production.

The capsule 1 according to FIG. 4 is likewise approximately cube-shaped.However, the side 1.1 lying on top in the figure is somewhat larger thanthe underside, so that, strictly from a mathematical viewpoint, thecapsule has the form of a truncated pyramid. The angle of inclination aof the side faces in the figure with respect to the perpendicular to thebase area—meaning of course the plane perpendicular to the base areaextending through the edge between the base area and the correspondingside face—is very small; it is preferably at most 2°, for example onlyabout 1°. Furthermore, the height of the capsule above the base areacorresponds approximately to the length of the edges of the base area,and for example deviates by at most 5% therefrom.

FIG. 5 shows very schematically the piercing of a side wall of thecapsule with a perforating element 3. Perforating elements for piercingthe capsule for the purpose of introducing or discharging liquid areknown and are also continuing to be developed. In principle, the capsuleaccording to the invention is suitable for any kind of perforatingmechanisms that have been developed for piercing the chosen capsulematerial with the chosen wall thickness, that is to say the specificform of the capsule according to the invention does not give rise to anyother requirements for the piercing mechanism than in the case of otherforms. Preferred, however, are arrangements in which a number ofdistributed perforating elements are present on the injector side and inparticular on the extraction side, and there is not just a centrallyprovided perforating element.

FIG. 6 shows a corresponding arrangement for piercing a capsule 1 froman edge. The arrangement has two perforating elements assigned to eachother in the direct vicinity of the edge, which perforate the sidesadjoining the edge in order that a liquid can be introduced ordischarged. Further pairs of perforating elements may be arranged alongthe length of the edge, or the two sides adjacent the edge may beassigned a different number of perforating elements. Piercing thecapsule from the corner is also conceivable, there then preferably beingat least three perforating elements, one for each side of the capsuleadjoining the corner.

The corresponding arrangement of perforating elements for discharging orintroducing purposes is preferably present on/at the oppositeside/edge/corner, asymmetric arrangements (introducing via an edge,discharging via a side face or the like) also being conceivable inprinciple.

A method for producing a capsule of the type described above isdiscussed below on the basis of FIGS. 7 and 8, the method correspondingto the first possibility mentioned. FIG. 7 shows a cube-shaped body 11open on one side, as can be produced, for example, by thermoforming. Theside walls 11.1 adjacent the opening, which lies at the top in thefigure, are inclined very slightly—by 1°—from the perpendicular to theside wall opposite the opening (‘bottom’), to be precise such that theopening is somewhat larger than the area of the bottom measured on theinner side. This optional feature has the effect that the cube-shapedbody can be stacked in a space-saving manner in the non-filled state.According to the invention, there is also the possibility of omittingthis slight inclination, in order to obtain an exactly cube-shapedcapsule; in this case, the non-filled, open cube-shaped bodies can nolonger be stacked well, and are for example advantageously transportedas bulk material.

In the region of the opening, a peripheral collar 12 is provided on theoutside of the open cube-shaped body and may protrude laterally quitedecidedly. As the detailed representation according to FIG. 8 reveals,this collar 12 has a ridge 11.5, which is directed upwardly (that is inthe direction of the open side) and has an upper edge (corresponding toa point in the cross-sectional representation).

The collar 12 with the ridge 11.5 serves as an aid in the fastening ofthe cover 13 by means of ultrasonic welding. For this purpose, the cover13 is put in place in the way illustrated in FIG. 8. Subsequently, asonotrode of an ultrasonic welding device is pressed from above (withreference to the orientation depicted in FIG. 8) against the cover andultrasonic vibrations are coupled into the latter. The collar 12 servesin this case firstly for applying an opposing force: before beingsubjected to ultrasonic vibrations, the body 11 filled with theextraction material is placed on a contact surface 15, such that itprotrudes into a square opening, shaped in a way corresponding to thecross section of the body, and contact surfaces with the collar 12against the edge of this opening. As a result, the body is fixed duringthe ultrasonic welding, and the necessary opposing force can be appliedindependently of the stability of the body 11. The ridge 11.5 serves asan energy director during the ultrasonic welding operation. In theregion of the ridge, ultrasonic energy is primarily converted into heat,so that the material of the cover 13 and the material of the body 11begin to melt in the vicinity thereof and are thus welded to each other.Instead of a ridge 11.5, or in addition thereto, the collar may alsohave other structures acting as energy directors, for example aplurality of tips, etc.

Following the ultrasonic welding operation, the collar may be removed bypunching. This produces the cube as represented in FIG. 3, at most withan only very slightly protruding (for example by no more than 0.1 mm)remaining collar 1.4, as represented in FIG. 2.

It is favorable for this purpose if—as represented in FIG. 8—the energydirector (here: ridge 11.5) does not lie as far outside as possible onthe collar, as known from the prior art, but on the inner side, in thevicinity of the inner wall of the body 11, since during the punching-offoperation the punching tool should preferably make contact outside thelocation at which the energy director was before the welding. Forexample, the distance d between the edge formed by the ridge 11.5 andthe inner wall is no more than 0.7 mm, with particular preference evenless, for example as a maximum 0.6 mm, 0.5 mm or 0.4 mm, and for examplebetween 0.25 mm and 0.4 mm.

Variants of the capsule body 11 (with a slight conicity shown somewhatexaggerated) and of the cover, as can be used for a production methodaccording to the second possibility (with the ultrasonic cut and sealprocess) are represented in FIGS. 9 and 10. A collar 12 of the capsulebody and a collar 13.2 of the cover are placed one on the other in ananvil and then detached by the ultrasonic cut and seal process,resulting in the cube-shaped capsule with a very slightly protrudingwelding bead. As a difference from the embodiment described above, thecapsule body has a slightly smaller height in comparison with the widthof the side walls, and the cover is outwardly curved (the curvature ofthe cover inner portion 13.1 can be seen very well in the figure) tomake up the missing cube height. As a result, the welding bead is offsetslightly from the upper end face, i.e. offset downwardly.

FIG. 11 shows an example of a capsule 1 produced by the ultrasonic cutand seal process mentioned above. The angle a, differing slightly from0°, of about 1° (see also FIG. 4), and the peripheral welding bead 14,which laterally protrudes on all sides by a maximum of about d=0.35 mmin the case of a cube size of 27.5×27.5×27.5 mm, that is by a maximum ofabout 3%, can be clearly seen. As already mentioned, the welding bead isslightly offset downwardly with respect to the upper end face.

FIGS. 12 and 13 show the brewing module with the capsule 1. In a wayknown per se, the brewing module has, guided between a framework withtwo vertical guiding walls, a discharge device 103 and an injector 104,which can be displaced in relation to each other by an operating leverthat can be pivoted about a pivot pin 106. In the embodiment depicted,the injector can be displaced by a pivoting movement of the operatinglever in the direction of the discharge device 103, while the latter isimmovable in relation to the framework.

In FIG. 12, the throwing-in opening 107 for throwing in the cubicportion capsule can be seen clearly. The throwing-in opening is formedin the framework, is located in the region of the discharge device 103and, like the latter, remains stationary during a movement of theoperating lever. The throwing-in opening may be slightly conical,tapering downward, in order to have a centering effect on the capsulewhen it is thrown in, without the risk of the capsule canting being toogreat.

In the operating state, the brewing module serves as a horizontalbrewing module of a coffee machine, which apart from the brewing modulecomprises a water tank, a water heating device (for example a flowheater) and a pump for feeding brewing water to the injector 104. Thecorresponding feed channels 118 of the injector may be formed in a wayknown per se; they are not the subject of the invention and are notdescribed any more specifically here. The injector also has at least onepiercing tip 112 with an assigned feed opening, so that the capsule canbe pierced and supplied with the extraction liquid through the feedopening. The coffee machine also has, for example, a capsule container,which is arranged underneath the brewing chamber and into which thecapsule is automatically ejected after the brewing operation by liftingof the operating lever.

The discharge device 103 is also provided with at least one piercing tip111 and an assigned discharge opening. Depending on the configuration,there is also a discharge line, by which coffee (or the like) emergingafter leaving the discharge device is conducted in such a way that itruns into a cup placed at the place intended.

As can be seen particularly well in FIG. 12, the discharge device 103forms a capsule receptacle with a contact surface 21 for the capsulethrown in through the throwing-in opening, defining the resting area 20.

Guided by the first side walls, the approximately cube-shaped capsulethrown in through the throwing-in opening when the brewing chamber isopen will rest on the contact surface 21.

The injector also has on each of both sides a pressing pin 32, which isprovided via a guiding plate 31 and can be displaced inwardly, counterto the spring force of a spring that is not represented in the figurebut is arranged between a collar 32.1 of the pressing pin and the sidewall 115, such that in a rest position it does not protrude inwardlybeyond the side walls 115 and in a deflected position it protrudesinwardly beyond the side walls and into the brewing space. The collar32.1 at the same time also forms together with the guiding plate 31 astop for the radially outward movement of the pressing pin 32.

The operating mode of the pressing pins 32 is clearly illustrated inFIG. 13. In the side part of the brewing module, a camway 42 isintegrated on each of both sides. Such a camway may be formed either inthe corresponding side wall itself or, as represented, in a camwayelement 41 fastened to the side wall. The pressing pin 32 is pressed bythe spring force outwardly against the camway 42. During thedisplacement of the injector 104 from the open position into the closedposition, it is deflected inwardly counter to the spring force, onaccount of the shape of the camway. As a result, the inserted capsule iscompressed on both sides; the inward deflection of the pressing pins maybe, for example, between 2 and 8 mm, with preference between 3.5 and 7mm. As a result, the coffee powder inside the capsule is compacted, inparticular in a central region. This also has the result of preventingbrewing liquid that flows through centrally from undergoing lessresistance than brewing liquid that flows along the periphery of thecapsule.

During the transition into the closed state of the brewing chamber, thecapsule is also easily displaced to the side where the discharge deviceis located, and thereby pierced on both sides—by the piercing tips 111of the discharge device and the piercing tips 112 of the injector.

Apart from compressing the extraction material, the pressing pins 32also have a further function. When the brewing chamber is opened afterthe brewing operation, they cause the capsule to be displaced out of thecapsule receptacle in the direction of the injector side in such a waythat it can fall downwardly and into a capsule container (not depicted).This takes place automatically, in that during the displacement of theinjector, the pressing pins 32 initially still reach into the interiorof the brewing chamber and fix the capsule; this fixing is only releasedapproximately in the position depicted in FIG. 12, in which the centerof gravity of the capsule is already beyond the resting area. Dependingon the degree of filling of the capsule, this effect is additionallyenhanced by the extraction material often being swollen after thebrewing operation, and therefore having the tendency to make the capsulewalls bulge slightly outwardly.

It can likewise be seen in FIG. 13 that the piercing tips 112 on theinjector side are a different distance apart than the piercing tips 111on the discharge device side. In the example represented, the piercingtips on the injector side are arranged decidedly further outward (hereat a distance apart of 19 mm) than the piercing tips on the dischargedevice side (here at a distance apart of 14 mm). It is generallypreferred that the distances between the tips are significantlydifferent, for example by at least 15%.

The brewing chamber is formed in such a way that, during the brewingoperation, no brewing water can get past the capsule and enter thedischarge device, and also that no extraction product flows anywhereother than into the discharge device.

1. A method for producing portion capsule for a coffee machine, thecapsule having a capsule wall, and having the form of a cube or cuboid,with the exception of a laterally protruding peripheral edge, the methodcomprising the steps of: producing a five-sided basic polyhedral bodythat is open on a sixth side, the body having a collar running around anedge of the basic body, filling the basic body with an extractionmaterial or extract; fastening a cover along the edge of the body suchthat the interior space produced is completely enclosed, wherein thecover is fastened to the basic body by ultrasonic welding, whereinduring the ultrasonic welding, the collar is at the same time at leastpartially detached by the effect of the ultrasound, or whereinsubsequently to the ultrasonic welding the collar is detached at leastpartially.
 2. The method according to claim 1, wherein the basic body ismanufactured by thermoforming.
 3. The method according to claim 1,wherein for the ultrasonic welding and for the detaching of the collar,the basic body is placed on a cutting anvil.
 4. The method according toclaim 1, wherein the cover has a same material composition as the basicbody.
 5. The method according to claim 4, wherein the cover has a samethickness as the basic body.
 6. The method according to claim 1, whereinthe basic body is manufactured so that the side faces of the basic bodyare inclined with respect to the perpendicular to the base area by anangle of inclination of at most 3°.
 7. The method according to claim 1,wherein the basic body and the cover are made of plastic.
 8. The methodaccording to claim 8, wherein the basic body and the cover are made ofpolypropylene.
 9. The method according to claim 1, wherein the capsulehas the peripheral edge laterally protruding by a maximum of 1.5 mm,wherein the peripheral edge is formed by a remaining portion of thecollar and a corresponding portion of the cover.